Purpose: To evaluate the feasibility, performance, and cost of a breast cancer screening program aimed at 40-49-year-old women and tailored to their risk profile with supplemental ultrasonography (US) and magnetic resonance (MR) imaging. Materials and Methods: The institutional review board approved this study, and informed written consent was obtained. A total of 3017 40-49-year-old women were invited to participate. The screening program was tailored to lifetime risk (Gail test) and mammographic density (according to Breast Imaging Reporting and Data Systems [BI-RADS] criteria) with supplemental US or MR imaging and bilateral two-view microdose mammography. The indicators suggested by European guidelines, US incremental cancer detection rate (CDR), and estimated costs were evaluated. Results: A total of 1666 women (67.5% participation rate) were recruited. The average lifetime risk of breast cancer was 11.6%, and nine women had a high risk of breast cancer; 917 women (55.0%) had a high density score (BI-RADS density category 3 or 4). The average glandular dose for screening examinations was 1.49 mGy. Screening US was performed in 835 study participants (50.1%), mostly due to high breast density (800 of 1666 women [48.0%]). Screening MR imaging was performed in nine women (0.5%) at high risk for breast cancer. Breast cancer was diagnosed in 14 women (8.4 cases per 1000 women). Twelve diagnoses were made with microdose mammography, and two were made with supplemental US in dense breasts (2.4 cases per 1000 women). All patients were submitted for surgery, and 10 underwent breast-conserving surgery. The sentinel lymph node was evaluated in 11 patients, resulting in negative findings in six. Pathologic analysis resulted in the diagnosis of four ductal carcinomas in situ and 10 invasive carcinomas (five at stage I). Conclusion: A tailored breast cancer screening program in 40-49-year-old women yielded a greater-than-expected number of cancers, most of which were low-stage disease. (c) RSNA, 2013

Axillary surgery in breast cancer (BC) is no longer a therapeutic procedure but has become a purely staging procedure. The progressive improvement in imaging techniques has paved the way to the hypothesis that prognostic information on nodal status deriving from surgery could be obtained with an accurate diagnostic exam. Positron emission tomography/magnetic resonance imaging (PET/MRI) is a relatively new imaging tool and its role in breast cancer patients is still under investigation. We reviewed the available literature on PET/MRI in BC patients. This overview showed that PET/MRI yields a high diagnostic performance for the primary tumor and distant lesions of liver, brain and bone. In particular, the results of PET/MRI in staging the axilla are promising. This provided the rationale for two prospective comparative trials between axillary surgery and PET/MRI that could lead to a further de-escalation of surgical treatment of BC. • SNB vs. PET/MRI 1 trial compares PET/MRI and axillary surgery in staging the axilla of BC patients undergoing primary systemic therapy (PST). • SNB vs. PET/MRI 2 trial compares PET/MRI and sentinel node biopsy (SNB) in staging the axilla of early BC patients who are candidates for upfront surgery. Finally, these ongoing studies will help clarify the role of PET/MRI in BC and establish whether it represents a useful diagnostic tool that could guide, or ideally replace, axillary surgery in the future.

Breast cancer (BC) requires the evaluation of tumor aggressiveness features to guide treatment decisions. Biopsy-derived prognostic information may differ from surgical histopathology due to tumor heterogeneity. Hybrid PET/MRI can provide additional information for tumor characterization, supporting initial therapy planning and prognosis. In this work, we acquired 157 BC patients using a hybrid PET/MRI scanner. The PET data were combined with ADC and semi-quantitative DCE-MRI metrics to derive “hybrid PET/MRI parameters.” Pathological data such as tumor grade, hormone receptors, proliferation index (Ki67), and surrogate molecular subtype were collected, and we evaluated their associations with hybrid imaging, also comparing with the PET and MRI data analyzed separately. Ki67 showed moderate correlations with PET, ADCmin, and most hybrid parameters. The PET and hybrid data differentiate histopathological factors, while ADCmin differentiates G1 vs. G2 and luminal A vs. luminal B. In the ROC analysis, hybrid SUVmax/ADCmin shows better performance to predict luminal B from luminal A (AUC 0.720, sensitivity 73.1%, specificity 63.2%, PPV 54.3%, NPV 79.7%) than SUVmean alone. Our findings suggest that these novel hybrid PET/MRI parameters may help the characterization of tumor tissue in IDC. However, a multivariate analysis is needed to confirm our preliminary results.

IntroductionAccurate staging at diagnosis is essential for optimizing treatment strategies and prognosis in early breast cancer (EBC). [18F]FDG positron emission tomography/magnetic resonance imaging (PET/MRI) is a hybrid imaging modality that enables simultaneous evaluation of locoregional disease and metastatic spread. This study assessed the impact of [18F]FDG PET/MRI on treatment planning in patients with EBC.MethodsThis unplanned sub-study derives from a prospective, interventional, single-arm clinical trial (SNB vs PET/MRI 2) conducted at San Raffaele University Hospital (Milan) between July 2020 and April 2024 (NCT04829643). Patients with EBC scheduled for primary surgery underwent additional preoperative [18F]FDG PET/MRI. The primary endpoint was the proportion of patients whose treatment strategy was modified based on PET/MRI findings. The secondary endpoint was the performance of PET/MRI in detecting multifocal breast cancer compared with standard imaging.ResultsA total of 264 patients, including five bilateral cases, were analyzed. [18F]FDG PET/MRI led to treatment plan modifications in 30.7% of patients. Surgical approach was altered in 23.9%, while 4.9% received primary systemic therapy and 1.9% were referred for systemic therapy alone. PET/MRI showed a sensitivity of 61.7%, specificity of 84.9%, positive predictive value (PPV) of 49.1%, and negative predictive value (NPV) of 90.4% for multifocal disease detection. When combined with standard imaging, specificity and PPV increased to 96.0% and 63.6%, respectively (p=0.001). Multifocal tumors detected by PET/MRI accounted for 15.2% of the cohort.Conclusions[18F]FDG PET/MRI significantly influences treatment decisions in EBC, modifying management in nearly one-third of patients. However, its moderate diagnostic accuracy warrants caution to prevent overtreatment.